Electronic devices, such as e-book readers, smartphones, tablet computers, and zero-emission electric vehicles, receive power from their batteries, which require recharge after some period of usage. One way to increase the capacity of these batteries and to extend battery life is to increase the mass of the battery, which in many circumstances is undesirable.
To recharge the device's battery without connecting to the power grid, solutions exist where the device is connected to an external secondary battery. For example, the device may be connected to an external battery pack, such as a battery pack that connects to the device via a proprietary interface (such as device “case” that includes a secondary battery). Provided herein are technical solutions to, among other things, problems related to battery-powered devices.